Kel, Psionic Sorcerer

At the beginning of your upkeep, exile the top
card of your library. Roll a d20.
1-14 | You may play that card this turn.
15-19 | You may play that card this turn without
paying its mana cost.
20 | You may play that card this turn without
paying its mana cost. When you cast an instant or
sorcery spell this way, it gains Storm (When you
cast this spell, copy it for each spell cast before it
this turn).